A Cylinder Pressure Sensor for Spark Advance Control and Knock Detection

A cylinder pressure time history has long been used as an indication of the performance of internal combustion engines. Recently the use of cylinder pressure has been proposed for the knock adaptive closed loop control of spark advance (1, 2)*. The ultimate practicality of such a scheme depends heavily on the cost and reliability of a sensor to make this measurement.

This paper describes the design, associated analysis, and the experimental performance of a potentially inexpensive sensor. The transducer is shown to be suitable for determination of the crank angle at the peak cylinder pressure and for detection of incipient detonation through the associated high frequency cylinder pressure oscillations. Furthermore, implementation of the sensor in a closed loop spark control system is briefly described. The sensor has proven to be adequate for spark advance control purposes.